• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.5 s.248
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• pp.457-464
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• 2006

Controlled auto ignition (CAI) combustion, also known as HCCI (homogeneous charge compression ignition), offers the potential to simultaneously improve fuel economy and reduce emission. CAI-combustion was achieved in a single cylinder gasoline DI engine, with a cylinder running in a CAI mode. Standard components were used the camshafts which had been modified in order to restrict the gas exchange process. The effects of air-fuel ratio, residual EGR rate and injection timing such as early injection and late injection on the attainable CAI combustion region were investigated. The effect that injection timings on factor such as start of combustion, combustion duration and heat release rate was also investigated. From results early injection caused the mixture to ignite earlier and burn more quickly due to the exothermic reaction during the recompression and gave rise to good mixing of the fuel-air.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.24-29
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• 1996

The purpose of this study is to propose new estimation method of unit cement content in hardened concrete. In general, the quantity of cement in hardened concrete is tested by hydrochlonic acid dissolving cement paste, however, hydrochloric acid dissolves sea shell contained in sea sand and lime stone in concrete. Therefore, the tested cement content is apt to estimate greater than actual cement content. The sodium gluconate solution dissolves only cement in concrete, it is hard to dissolve sea shell and lime stone as CaCo3. The effects of the quantity, concentration and temperature of sodium gluconate solution, the ignition temperature, the ignition loss of cement on the cement content and the percentage of dissolution of cement were investigated to establish a test method. From the results of these tests, the fundamental test method for cement content of hardened concrete by sodium gluconate is proposed.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.6
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• pp.30-40
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• 1995

Optically accessible D. I. diesel engine with a rectangular combustion chamber was constructed to visualize the behaviors of sprays and flames in the combustion camber with the close conditions of pressure and temperature in an actual engine. The behaviors of sprays and flames in the combustion chamber as the operating conditions of this engine were photographed with high speed camera by Diffused Background Illumination Method. With photographs taken by this method, behavior of spray droplets injected into the combustion chamber, ignition points, and flame propagation were observed and analyzed at a time-and space-dependent fashion.

• Journal of the Korean Society of Combustion
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• v.17 no.2
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• pp.24-31
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• 2012

Diesel engines exhaust much more NOx(Nitrogen Oxides) and PM(Particulate Matter) than gasoline engines, and it is not easy to reduce both NOx and PM simultaneously because of the trade-off relation between two components. This study investigated flame characteristics of the partial premixed compression ignition known as new combustion method which can reduce NOx and PM simultaneously. The investigation was performed through the analysis of the flame images taken by a high speed camera from the visible engine which is the modified single cylinder diesel engine. The results obtained through this investigation are summarized as follows; (1) The area of the luminous yellow flame was reduced due to the decrease of flame temperature and even distribution of temperature. (2) The darkish yellow flame zone caused by the shortage of the remaining oxygen after the middle stage of combustion was considerably reduced. (3) Since the ignition delay was shortened, the violent combustion did not occur and the combustion duration became shortened.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.1
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• pp.205-212
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• 1998

In this study, the effects of water vapor in inlet air on combustion efficiency, general performance, knock characteristics and emission gas concentration were investig- ated through the experiments of combustion and vibration analyses, emission gas analysis by changing water vapor quantity in inlet air with temperature and humidity auto control unit. With partial vapor pressure increase, the brake torque at wide open throttle status decreased and the average ignition delay angle increased, IMEP (indicated mean effective pressured using the integral and 3rd derivatives of filtered cylinder pressure as knock intensity, which matched well with the method of frequency power spectrum of block vibration signal. Water vapor in intake air had influence on the spark knock sensitivity. With the increase of water vapor content in intake air NOx emission was decreased and HC emission was increased.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.39-47
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• 2003

UEGI (Unburned Exhaust Gas Ignition) is an alternative method for fast light-off of a catalyst. It ignites the unburned exhaust mixture using two glow plugs installed in the upstream of the close-coupled catalysts. In addition, a hydrocarbon adsorber was applied to the UEGI, for more effective reduction of HC emission. Engine bench tests show that the CCC reaches the light-off temperature laster than the baseline exhaust system and HC and CO emissions are reduced significantly during the cold start. From the vehicle test, it was observed that a few amount of HC emission was reduced even the catalysts were aged. It is expected to develop a solution kit applicable to a new vehicle or used one, to meet the emission regulation

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.5
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• pp.24-29
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• 2007

This study aims to provide a fundamental data for directly injected hydrogen fuel engines. Spray, ignition and combustion characteristics of hydrogen were studied using constant volume chamber. For spray visualization, hydrogen was vertically injected into a combustion chamber at various condition, for example, injection pressure, ambient pressure. And an argon laser was used for the shadowgraph photography by applying optical method. Also, to investigate heat-release rate and flame propagations, spark was ignited on hydrogen injected at the different time after injection and the duration of injection was also changed. Processes of ignition and combustion were analyzed by heat-release rate calculated by pressure history and were observed by shadowgraph photography The results gave much knowledge of spray, ignition and combustion characteristics of hydrogen.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.3
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• pp.148-154
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• 2007

In this paper, characteristics of ignition voltage and current by wire length of HID(High Intensity Discharge) lamp circuit are analyzed. In the construction field, decision of the wire thickness for HID lamp circuit has the problems, and these are presented. Through transmit parameters, equivalent model of the ballast and HID lamp circuit was derived. The graph of voltage reduction about length between the ballast and the lamp is shown. The simulation of proposed model and experimental results are presented in order to validate the proposed method. The proposed model and graph can use to choose the proper length of wire between the ballast and the lamp in the field.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.255-263
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• 2006

In order to measure the acoustic amplification factor of an Al/HTPB propellant, T-burner tests using pulsed DB/AB method were conducted. In the experiment, powdered aluminum content was varied to a certain extent. Simultaneous ignition on the internal surface of a propellant was achieved by the use of a fast ignition disk. From the experimental data, the damping factor for a non-zero aluminum content could not be calculated due to the fast attenuation of perturbed pressure. Therefore, the addition of aluminum particle was more than sufficient to stabilize pressure-coupled instability.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.75-81
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• 2004

The metal halide lamps are now widely used in the application and commercial lighting due to their attracting properties such as good color rendering and high efficiency. But, they have the serious problem of acoustic resonance for high frequency operation and they need the high voltage to ignite. So, they have not been applied to indoors. Over the past few years, a considerable number of studies have been conducted on the electronic ballast together with hot restarting and resonance phenomenon. But, very few attempts have been made with the adaptive ignition method according to the lamp state. In this paper, electronic ballast is proposed for metal halide lamps with an igniter for adaptive ignition. The proposed electronic ballast can generate different ignition voltages according to the arc tube state.